The present invention relates to an image forming apparatus of the so-called "shell type" whose main body is divided into an upper unit and a lower unit and, more particularly, to an image forming apparatus arranged to move a document table upon which an original document is placed and thereby scan the image information of the document.
An image forming apparatus of the so-called "shell type" is generally known as one type of an image forming apparatus arranged to form an image of an original document onto a sheet of paper in accordance with the image information from the document. It is arranged such that its main body is divided into an upper unit and a lower unit and is made openable by rocking the upper unit with respect to the lower unit in order to make the maintenance and jam elimination easy.
Further, an image forming apparatus of the type wherein an original document is scanned by the formed and backward movement of a document table having this original document placed thereon is known as one of the above-mentioned image forming apparatuses of the "shell type". In this type of image forming apparatus, a driving mechanism for driving the document table is provided, which is intended to move the document table in the forward and backward directions. This driving mechanism is such that at the time of scanning the document the document table is forwardly moved and, when the document table is brought back to its original position after the scanning, is backwardly moved. Conventionally, with regard to this type of image forming apparatus, it was possible that when the main body is opened or closed for the purpose of performing the maintenance and jam elimination, the document table is caused to incline and thereby caused to slide or slip down. In order to prevent the document table from slipping, conventionally, the apparatus is provided with a locking mechanism which permits the document table to be locked at the time of opening the main body, or alternatively provided with a mechanism which permits the main body to be opened only when the document table is located at its lowermost position.
The above-mentioned known image forming apparatus, therefore, has a drawback in that it is complicated in construction and high in manufacturing cost.